The effects of commonly prescribed psychotropic drugs such as methylphenidate, pemoline, and dextroamphetamine on the behavior of children from about 5 to 12 years of age who display hyperactivity, impulsivity, and are diagnosed as MBD (minimal brain dysfunction) will be systematically studied. A number of measures will be used to assess drug effects: teacher, parent, and physician rating scales; observer monitoring and video taping of classroom behavior; short-term memory tasks; psychological tests such as intelligence tests and impulsivity tests; cardiovascular measures of heart rate and blood pressure under rest and mild exercise stress; growth in height, weight, and body composition; gas chromatographic and mass spectrometry analysis of metabolites in the blood and urine; and psychophysiological monitoring of attention. An anterospective long-term follow-up will be continued with about 100 children who received stimulation medication (some for 6 years), on children whose medication has been discontinued, and on cohort children. Studies of dose-response relationships between mg/kg doses of psychotropic drugs and learning performance, arithmetic, and social behavior in classrooms will be conducted. BIBLIOGRAPHIC REFERENCES: Sprague, R.L., & Gadow, K.D. The role of the teacher in drug treatment. In J.J. Bosco & S.S. Robin (Eds.), The hyperactive child and stimulant drugs. Chicago: University of Chicago Press, 1977. Sprague, R.L. & Sleator, E.K. What is the proper dose of stimulant drugs in children? In R. Gittelman-Klein (Ed.). Recent advances in child psychopharmacology. New York: Human Sciences,1977.